That's why Gary Smith, CEO of Ciena, a broadband and telecommunications company, says his best piece of advice for recent college graduates is to recognize the importance of relationships, and how they can make to break your career.

In a recent interview with Adam Bryant of The New York Times, Smith says the most important lesson that he has learned during his career in leadership is: "Relationships really matter, and you need to get that right, both for your career as an individual and as a future leader."

"I think a lot of people pay attention to the technical stuff and the hard stuff about whatever discipline they're in," he tells Bryant. "But it's the softer side that will get you every time if you're not paying attention to it. It's probably the biggest determinant of whether you're going to be successful."